Riot, Secluded Cube

When Riot, Secluded Cube enters the battlefield, exile target nonland permanent until Riot, Secluded Cube leaves the battlefield

{x}{t}: Exile target permanent with mana value X unless it's controller pays {2}

Therapy {x}: Any player may activate this ability to pay X plus {2} where X is equal to the mana cost of target card exiled by Riot, Secluded Cube to remove the targeted card from exile.
"Cubemaxxing for the day."-Riot, Depressed